Ever since the banning of the pesticide DDT, which weakened eggshells, bald eagles have been making a comeback in the Great Lakes region. In Michigan, however, that recovery has been lackluster, and researchers have found one potential reason why: flame retardants and pesticides in the blood of eagle nestlings.

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"(Eagles) have recovered mostly, but not to what was expected," said Marta Venier of Indiana University. Venier is the lead author of a paper in the August issue of the journal Chemosphere, which describes a "snapshot" of what is in eagle nestlings' blood in near lakes around Michigan.

Venier and her colleagues were able to collect blood samples of bald eagle nestlings in the Great Lakes region by arduously climbing trees, bagging the large nestlings and carrying them carefully to the ground to draw a small sample of blood. The birds were then returned to their nests angry, but unharmed.

Tests on the blood show that the national symbol of the United States is ingesting flame retardants and pesticides via its food. The chemicals are originally from pesticides or foam padding for furniture and mattresses, which contain a variety of flame retardants.